Thursday, August 30, 2007

Me neither. But they're out there...and they're dangerous.This guy tells this story on how a simple faulty adapter can become a real virus...in this case, since it affects hardware, it's a "mechanical virus".

Mac users have to use a DVI to VGA adapter in order to connect to the normal VGA overhead projectors. Every so often, Mac users at this guy's workplace started noticing that they could no longer connect to the projectors at the meeting room. Well, they were able to physically connect but nothing happened after that. No image, no connection, nothing...

But the strangest thing was that not all Mac users were affected, and after some heavy "mechanical" debugging, this guy discovered the problem source at the DVI to VGA adapter. All Macs that used this adapter to connect to the projector were "infected".

But exactly what was the problem? Read his explanation:

"If you’ve never seen a DVI port before, it’s a long thin port with lots of pins arranged in a rectangular pattern. These pins on the cable plug into matching holes on the computer. The pins are relatively close together, so the holes are separated by thin walls of plastic with metal contacts. The problem I discovered was that one of the thin walls between the holes had broken and bent down, forming a ramp. When I plugged the DVI adapter into my computer, two of the pins went into the same hole, and the projector could no longer understand the output from my computer. However, it doesn’t end there. When I plugged the DVI adapter into the broken socket, the ramp formed by the broken wall bent the corresponding pin upwards, forming a wedge with the adjacent pin. Then, when any other Mac user plugged the same adapter into their own computer, the pin wedge would press down on that same socket wall, breaking it and bending it down in the same fashion."

He ends the story with an interesting note on how these "mechanical virus" can be perceived as any other normal computer virus and how people act accordingly:

"Once the virus was discovered, people began to take measures to protect themselves. I just started checking every DVI adapter that I used on my computer (being careful). Others got their own DVI adapters and started using them exclusively (using protection)."